The problem might be that RPGs acquired a reputation as a dumb genre. Younger people play relatively complex non-actiony games like Crusader Kings or Rimworld just fine. They play challenging 'get gud' games like DOTA or Hearthstone. But with an RPG, they expect to see a movie with simplistic gameplay. Alternatively, they expect a NES graphics style game, where the movie is replaced with simple non-interactive one-liners.
Reading does seem to have something to do with it, but young people read a fair deal of dumb YA, so I wouldn't blame it on not reading books, but rather not liking to read in games for some reason.
It's just a lack of interest.
I have a brother who's a hardcore Starcraft 2 player. It's all he plays. All day. Every day. When he's on break from work; he's instead spending his break not sleeping by playing that game. I managed to get him to play Dark Sun by sitting by his side and walking him through it. He had fun creating his party. Rolling for stats and asking question. Thing is, even though he was enjoying the experience. Next day. He was back to playing Starcraft 2 and never touched Dark Sun ever again. It was the same thing with Star Wars: Knights of the Old Republic. He was running around. Exploring the first world you crash into from opening. Talking to every fucking NPC. Reading every boring dialogue. Very much liking the game. However. Come morning. He completely forgot about it and went back to Starcraft 2.
Thing is. RPGs aren't this mystical thing that young people are unable to fathom due to some generational thing or some retarded bullshit. They're pretty easy to bite into and chew, especially if you had those handy dandy manuals that games used to ship with - which basically explain every nuance in concise manner, some manuals also had enemy lists, listing their weaknesses and how to beat them - essentially telling you how to chew your own food. There were also Cluebooks too. Which gave you the best way to beat the game as quickly as possible without any fuss. Nowadays RPGs don't have cluebooks or manuals. Instead it's all explained through in-game tutorials, tool tips, hints, though most people just search things up online if they have problems, having it explained by some other schmuck. Anyways. The genre is very approachable and accessible.
Truth is: Your young gamers aren't going to pull themselves away from Fortnite, League of Legends, DOTA, Starcraft, or whatever recent online multiplayer; to play something that they're simply not interested in. Yeah you can force them by sitting by their side, walking them through it, but they'll just go back to Starcraft or Fortnite the next day.